JPS5857700B2 - Aspheric lens measuring device - Google Patents

Description

[Detailed description of the invention] The present invention relates to an apparatus for measuring the shape of an aspheric lens.

In a conventional aspheric lens measuring device, a member holding a lens to be measured is swung by a predetermined rotation angle around an axis perpendicular to the optical axis of the lens, the rotation angle is detected, and the lens to be measured is measured. A movable stage that holds the stylus in contact with the stylus is provided so as to be slidable in the optical axis direction of the lens, and the movable stage is moved by the movement of the point of contact with the stylus in the optical axis direction that occurs when the lens to be measured oscillates. The characteristics of the aspherical lens were determined from the amount of displacement and the rotation angle.

However, with such conventional devices, it is necessary to always keep the stylus in contact with the surface of the lens to be measured, and if the biasing force for making this contact is weak, measurement errors may occur, and if the biasing force is too strong, If too much is used, there is a risk that the stylus may damage the lens surface.

The present invention aims to solve these drawbacks and provide an aspheric lens measuring device with extremely small measurement errors.

The present invention continuously detects the rotation angle at the moment of the rocking motion of a member that holds the lens to be measured, and detects the slidable movement of the lens to be measured in the optical axis direction in the rocking reference position direction. A stand is provided, and the movable stand is slid in accordance with the rotation angle by an amount that matches a predetermined (calculated) shape characteristic of the surface of the lens to be measured that passes through the rocking reference position when swinging. The lens to be measured is measured by reading the change in the distance between the lens surface and the movable table at the swing reference position.

Next, one embodiment of the present invention will be described in detail.

In the figure, reference numeral 1 denotes a member for mounting the object to be measured, and a mounting portion 1a for mounting the lens 2 to be measured is formed at one end.

Reference numeral 3 denotes a central axis perpendicular to the optical axis of the lens 2 to be measured, at one end of which the member 1 for mounting the object to be measured is fixed, and the device body 41
There are 9 rotatable units installed.

The central shaft 3 is configured to be reciprocated by a predetermined rotational angle by a drive source 9 (not shown), and to swing within the range of engagement between the lens 2 to be measured and a head 7a of a roughness meter 7, which will be described later.

A rotation angle detector 5 is constructed to constantly detect the rotation angle of the central shaft 3.

Reference numeral 6 denotes a movable table, which is provided so as to be able to slide in the same direction (in the direction of the arrow) as the optical axis direction in the swing reference position direction ρ of the lens to be measured.

7 is a roughness meter such as an electric micrometer, and the movable table 6
The head 7a is fixedly attached at its tip and is biased so as to constantly engage the lens to be measured 29, and is provided so as to detect minute displacements in the distance between the contact end and the movable table. .

The contact end is configured so that it always passes on the optical axis when the lens 2 to be measured is oscillated.

Reference numeral 8 denotes a reduction lever, one end of which is rotatably supported by the device main body 41 and a support shaft 99; the roller 10 that engages with one end of the moving table 6 is rotatably supported; A roller 11 that engages with an interlocking piece 12 that slides in the direction of the arrow in conjunction with an actuator 14c (described later) is rotatably supported on a shaft.

Reduction lever 8, support shaft 9, rollers io, 1i, interlocking piece 12
constitutes an interlocking member that reduces the amount of displacement given by the actuator 14, which will be described later, and transmits it to the movable table 6.

Reference numeral 13 denotes a computer, which adjusts the lens to be measured 2 to a predetermined value based on the detection signal given from the rotation angle detector 5.
In order to slide the movable base so that the distance between the contact point with the roughness measuring head 7a and the movable base when the movable base has an aspherical shape (calculated) is constant during the rocking. The controller is provided to calculate data based on the detection signal according to a program installed in advance, and to output the result as a pulse signal.

Furthermore, the computer 13 is configured to display the amount of minute displacement detected by the roughness meter 7.

14 is an actuator driven by a pulse motor, which receives a pulse signal from the computer 13;
The interlocking piece 124 is configured to provide reciprocating linear motion.

Reference numeral 15 denotes a laser interferometric length measuring device, which is provided to constantly measure the amount of displacement of the movable table 6 and at the same time transmit measurement data to the computer 131.

With such a structure, in order to measure an aspherical lens, the object to be measured is mounted by swinging the member 1 together with the lens 2 to be measured by a predetermined rotation angle about the central axis 3, and The angle of rotation at this point is continuously measured by the rotation angle detector 5I, and the data is transmitted to the computer 13.

The computer 13 calculates from the data and generates a pulse signal corresponding to the rotation angle l of the central shaft 3, actuates the actuator 14, and moves the movable table 6 in the direction of the arrow via the interlocking members 7 to 11.

At the same time, the amount of displacement of the movable table 6 is constantly measured by the laser interferometric length measuring device 15 and fed back to the computer 13, and the computer 13 compares the calculation result with the measurement result by the laser interferometric length measuring device 15I. If there is an error, the operation of the actuator 14 is corrected.

The roughness meter 7 is a head 7 that is always in contact with the lens 2 to be measured.
A change in the distance from the contact end of a to the movable table 6 is detected, the detected data is transmitted to the computer 131, and the computer 13 displays it.

Therefore, when the lens to be measured has a predetermined aspherical shape, the movable stage 6 always slides a constant distance 9 from the contact end with the head 7a to the movable stage 6, so that
If the lens to be measured is an aspherical lens having an error from a predetermined shape, the distance changes in accordance with the rocking of the lens and is detected by the roughness meter 7.

As described above, according to the present invention, there is no need to slide the movable table by the lens surface to be measured, so the lens surface is not damaged, and ultra-precise aspheric surface measurement with very few errors can be performed. can be done.

Furthermore, by providing a reduction mechanism in the interlocking members 7 to 11, it is possible to reduce errors in the amount of displacement caused by the actuator and further improve accuracy.

[Brief explanation of drawings]

The drawing is a schematic side view of an embodiment of the invention. Explanation of the symbols of the main parts: 1... Member for mounting the object to be measured, 2... Lens to be measured, 5... Rotation angle detector, 6...・Movement table, 7...Arasa meter, 8...Reduction lever, 12...
Interlocking piece, 13... Computer, 14...
...Actuator, 15...Laser interference length measuring device.

Claims (1)

[Scope of Claims] 1. A mounting device formed to mount a lens to be measured and provided so as to be swingable at a predetermined rotational angle about an axis orthogonal to the optical axis of the lens to be measured is a member and For mounting the object, a movable stage is provided to be slidable in the optical axis direction of the lens to be measured at a swing reference position σ of the member; A rotation angle detection member detects the rotation angle, and a predetermined shape characteristic I of the lens to be measured corresponding to the rotation angle is detected from the rotation angle detection member based on a predetermined program for sliding the movable base. a control member that issues a control signal calculated as a detection signal input; an actuating member that displaces the movable base in accordance with the control signal; and a measuring member that measures the amount of displacement of the movable base and transmits the measurement data to the control member. and an aging meter, which has a needle part that is always in contact with the lens to be measured, and is provided on the movable base so as to detect a change in the distance between the contact end of the needle part and the movable base. and that the control member is provided with means for correcting the control signal based on the measurement data and calculating and displaying the characteristics of the lens to be measured from detection signals from the rotation angle detection member and the roughness meter, etc. A measuring device for aspherical lenses. 2. The actuating member according to claim 1, wherein the actuating member is formed of a driving part for giving an amount of displacement and an interlocking part for reducing the amount of displacement and transmitting the reduced amount to the moving table. measuring device. 3. The measuring device according to claim 1 or 2, wherein the calculating and displaying means is the control member.